Intrinsic factor is a glycoprotein that parietal cells in the stomach produce to help the small intestine absorb vitamin B12, according to Global Healing Center. Intrinsic factor dissolves in the small intestine so that vitamin B12 can bind with the protein transcobalamin II for transportation to the liver.
An inability to produce intrinsic factor leads to a condition known as pernicious anemia, explains Global Healing Center. In such a case, the body requires regular injections of vitamin B12 since it cannot absorb it. The body typically obtains vitamin B12 in the diet from animal products such as fish, meat, liver, eggs or dairy. Vitamin B12 is essential for DNA synthesis and formation, red blood cell creation and brain function.